Dynamic covalent nanoparticles: towards universal nanoscale synthons
Abstract
Unlocking the full technological potential of nanomaterials demands a new era of synthetic chemistry incorporating nanoscale building blocks that is just as predictable as present-day chemical technology based on molecules. This requires a move away from the prevailing strategies for engineering nanoparticle surface chemistry, which have limited capabilities and tend to be specific to each different nanoparticle type. We have recently introduced thermodynamically controlled covalent reactions to achieve programmable modification of surface chemistry on prototypical spherical gold nanoparticles. Guided by real-time characterization of the molecular-level processes in situ, we have demonstrated highly specific and reversible molecular transformations at the nanoparticle surface, generating fundamental understanding about reactivity at nanoscale interfaces and enabling, for example, stimuli-responsive tuning of nanoparticle properties or construction of covalently linked but adaptive hybrid nanoparticleÐmolecule assemblies. We now aim to develop dynamic covalent nanoparticles (DCNPs) as a unifying platform technology for chemically manipulating a wide range of colloidal nanomaterials. The DCNP concept is unique in that it achieves reversible, stimuli-responsive modifications while using robust and structurally unambiguous all-covalent structures. Thermodynamically governed reactions allow easy modulation of the extent of reaction and a wide range of reactivity behaviors (rates, activation methods, environmental compatibility) are accessible. Our divergent building block strategy envisages just a small number of carefully designed DCNP starting points that can be modified in a controlled manner using universal, operationally simple methods to produce a wide range nanoparticle products and materials with high selectivity. The next critical step in developing this versatile DCNP toolkit is to extend the methodologies to a wider suite of nanoscale scaffolds. We will expand the scope in three key features of the NP core Ð size, shape and material Ð developing robust modification protocols in each case. By interrogating the transformations in situ using analytical methods that attain molecular sensitivity (e.g. 19F NMR), we will establish fundamental structureÐreactivity understanding for interfacial processes while also probing the influence of each structural feature on surface-confined molecular reactivity. We will exemplify the technological potential of the DCNP toolkit by developing capabilities including directional linking of anisotropic nanostructures (e.g. tip-to-tip assembly of nanorods) and chemoselective assembly of adaptive aggregates that incorporate more than one type of nanoparticle with control over aggregate composition and size. The combination of synthetic programmability and predictive understanding of molecular reactivity, allied with the flexibility and versatility of dynamic covalent reactivity, mean that this work will pave the way towards a general synthetic science for colloidal nanomaterials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010233
Entities
People
- Euan R Kay
Organizations
- Army Contracting Command
- United States Army
- University of St Andrews